Prevent iframe tag from being filtered by excerpt function.

I’ve been having trouble getting the soundcloud player I have embeded in the first post with iframe on the website to show up in the excerpt (I tried using the direct link too and it still doesn’t show up). From what I’ve read, by default, wordpress ignores HTML tags in the excerpt. I’ve tried quite a few solutions, including plugins and changing the functions.php code but haven’t had any luck.